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Textile manufacturing is one of the major industries that discharge an enormous quantity of dyes over the printing and dyeing process. Accordingly, the increasing demand for efficient and inexpensive treatment has enabled the innovation of low-cost alternative adsorbents. In this study, agricultural biomass from the Moroccan Sahara (ABMS) was investigated as an ecofriendly and low-cost biosorbent of textile dye. The effect of independent variables affecting the process fixed-bed adsorption such as inlet textile dye concentration (40, 80, and 120 mg L-1), flow rate (2, 4, and 6 mL min-1) and bed height (5, 10, and 15 mm), were modeled and evaluated by response surface methodology based on the Box-Behnken design. The kinetic models, Thomas and Yoon and Nelson model were applied to experimental data to predict the breakthrough curves using linear regression and to determine the characteristic parameters of the packed bed column. The data were in good agreement for both models with R² > 0.95. The maximum Methylene blue dye removal capacity was found to be 30.15 mg g-1. These findings suggested that ABMS biosorbent without any activation in the column structure presents great potential in the removal of dyes from textile wastewater. [ABSTRACT FROM AUTHOR]

Highlights: [•] Calcined eggshells considered as new and eco-friendly biosorbent to remove cationic dyes. [•] Biosorption kinetics of basic yellow in a batch system was found to conform to pseudo-second order model. [•] Biosorption equilibrium was well described by the Freundlich isotherm model. [•] Thermodynamic studies indicated that biosorption process was spontaneous, endothermic. [•] Isotherms errors analysis shows that biosorption of basic yellow onto calcined eggshells is well fitted by Freundlich isotherm model. [ABSTRACT FROM AUTHOR]

Highlights: [•] Calcined Mussels shells considered as new and eco-friendly biosorbent to remove dyes. [•] Biosorption kinetics of Rhodamine B, Alizarin Red S and Orange II in a batch system was found to conform to pseudo-second order model. [•] The biosorption equilibrium was well described by the Langmuir isotherm model. [•] Thermodynamic studies indicated that biosorption process was spontaneous, endothermic for Alizarin Red S and Orange and physical reaction. [•] Thermodynamic studies indicated that biosorption process was spontaneous, exothermic for Rhodamine B and chemical reaction. [Copyright &y& Elsevier]

Abstract: The efficacy of calcined bone (CB) powder prepared from bones waste was investigated in this study as a novel biosorbent for the elimination of dye molecules from contaminated streams. Removal of safranin as a cationic dye model by CB from aqueous solutions was studied under different experimental conditions. The selected parameters were biosorbent dose (20–160mg), contact time (0–90min), dye concentration (20–100mg/L) and temperature (30–60°C). The biosorption capacity of safranin improved from 81.67 to 107.67mg/g at 90min contact time when the safranin concentration was increased from 20 to 100mg/L. The kinetic analysis showed that the pseudo second-order model had the best fit to the experimental data. The Langmuir and Freundlich equations provided the best fit for the experimental data of the equilibrium biosorption of safranin onto CB at different temperatures. In addition, the maximum biosorption capacity increased from 93.12 to 135.32mg/g when the temperature was increased from 30 to 60°C. The thermodynamic evaluation of safranin biosorption on CB revealed that the biosorption phenomenon under the selected conditions was a spontaneous physical process. Accordingly, CB was shown to be a very efficient and low-cost biosorbent, and a promising alternative for eliminating dyes from industrial wastewaters. [Copyright &y& Elsevier]